We have encountered show-stopper bugs in the freebsd.org cluster when trying to use dma as a drop-in sendmail replacement. This is a tracking bug.
Do we need .forward files to work? That's not supported by DMA either
I believe the two depends-on issues are now resolved.
(In reply to Mark Felder from comment #1) I'd say .forward isn't absolutely required for DMA's intended use case but would be nice to have. There is an open upstream issue for .forward file support in https://github.com/corecode/dma/issues/37.